Re: Since you mentioned plastic cards
There are several ways to pay with it. The QR code can be used both ways. Eg, a website will present you with a QR code when you get to the payment stage, you scan it with your phone, done.
I've not yet had a chance to use it much, but from my many relations in China, there is no doubt its convenience has been enthusiastically adopted by the general population. It's now ubiquitous, when just 5 years ago, it simply did not exist.